This invention relates to methods for making accurate measurements of capacitance and displacement.
Despite the improvements that have been made in measuring small distances, there remains a need for a simple, yet highly-accurate technique for producing a digital representation of such distances. It is known to make distance measurements by relying on changes in the capacitance between two plates, but known techniques tend to first linearize for the inverse relationship between distance and capacitance, and then digitize the linearized signal. For example, a circuit known as a capacitive pump is used to generate a current proportional to capacitance. The current is linearized, and then converted to digital form.
In other measurement applications, analog to digital conversion has been performed using what is known as dual-slope integration. For example, dual-slope integration has been used in measuring resistance.